THE HISTORIC CHRONOLOGY of many medical devices is often based on the dates of the patent submission and final approval with little emphasis placed on the “prior art” that preceded the patent. There is no better example of this chronology confusion than the controversy surrounding who invented the first corneal contact lens.

In the late 1800s, a young French ophthalmologist, Eugène Kalt, MD, experimented with 16.0mm to 22.0mm glass scleral lenses, as well as ground glass corneal lens designs that had overall diameters of 11.0mm, 11.5mm, and 13.0mm (Bowden, 2009). Unfortunately, he never published the results of his corneal lens experiments.

So, we need to rely on Dr. Kalt’s personal communication with French ophthalmologist Emile Haas, which he presented to the Paris Society of Ophthalmology in 1937 (Bowden, 2009). Dr. Kalt reported that his glass corneal lenses were heavy and could not be retained on the eye by the effects of surface tension alone, a problem that would not be overcome until the introduction of plastic (polymethyl methacrylate [PMMA]) corneal lenses in the 1940s (Heitz, 2003).

This story leaps forward 57 years to December 1945, when Ohio optometrist Dr. Dennis C. England applied for the first non-scleral lens patent for 7.8mm to 11.5mm PMMA contact lenses that rested directly on the corneal surface (England, 1946). Dr. England manufactured his first corneal lenses in 1944 by cutting out the centers of molded PMMA scleral lenses and rounding the edges.

Note: The tools he used to produce these lenses and a copy of his 1945 patent application are on file at the Contact Lens Museum in Forest Grove, OR. Dr. England’s patent was denied on Oct. 10, 1946, based on the patent examiner’s belief that corneal clearance (as seen with scleral lenses) was a primary requirement for comfortable contact lens wear and that prior art existed through Dr. Kalt’s work with glass corneal contact lenses.

Enter Kevin M. Touhy, who in most historical references is given credit for the first corneal lens. In 1945, Tuohy left Obrig Laboratories in Montreal to join Solon Braff, OD, and lab manager Xavier Villagran at Los Angeles-based Solex Laboratories (Pearson, 2022). The next year Villagran showed Dr. Braff and Obrig the center of a scleral lens that he had inadvertently cut out. Tuohy refined the production of the 11.5mm to 12.0mm PMMA lenses. Then, on Feb. 28, 1948, Tuohy submitted a patent application, listing himself as the single inventor (Figure 1) (Tuohy, 1948). As history would have it, this patent (thanks to a more lenient patent reviewer) was officially granted on June 6, 1950 (Bowden, 2009).

The initial Tuohy lens had two posterior curves. The central posterior curve (CPC) was 10.5mm and was usually fit 1.50D flatter than the flattest K measurement. The peripheral curve was 0.5mm wide. Over time, it was noticed that Tuohy lenses that were inadvertently fabricated too small were better tolerated than the initial design (Girard, 1970).

Sadly, Tuohy took his own life in 1968 at the age of 40. It has been suggested that guilt may have played a part in this, as Xavier Villagran always maintained that he was the true inventor of the modern corneal contact lens. CLS

References

1. Bowden TJ. Contact Lenses the Story: A Historical Development of Contact Lenses. Bower House Publications. 2009:40-49.
2. Heitz RF. History of Contact Lenses, Volume One, Early Neutralizations of the Corneal Dioptric Power. University of Strasbourg, France. Historical and Philological Sciences EPHE, Paris. Translated by Colin Mailer. London Ontario Canada. Publisher, G. Schmidt, Van Iseghem Laan 131, B- 8400 Oostende, Belgium 2003.
3. England DC. Ophthalmic Contact Lens. US Patent Application #642117 Division 7. January 19, 1946 Jan 19. Patent Attorney: William S. McDowell Columbus, Ohio.
4. Pearson RM. The 75th anniversary of the Tuohy contact lens: A review. Cont Lens Anterior Eye. 2022 Sept 26:101756. [Online ahead of print]
5. Tuohy K. Contact Lens. 1948; US2510438A. Available at patents.google.com/patent/US2510438A . Accessed Jan. 5, 2023.
6. Girard L. Corneal Contact Lenses, Second Edition. C. V. Mosby Publisher. 1970:12-13. Additional source: Bailey NJ, Barr JT. The First 100 Years. Contact Lens Spectrum, Special Edition. 1987 Jul.